1. Field of the Invention
The present invention relates to a clamping member disassembling device and method for disassembling a clamping member from base metals, the clamping member comprising a head portion and a body portion being inserted into clamping holes formed in the base metals, the head portion being in contact with a peripheral edge portion of one of the clamping holes, the clamping member thus clamping the base metals, as well as an attachment structure thereof and a production system using the disassembling method.
2. Description of the Related Art
As techniques for joining base metals such as steel plates or plastic plates or for connecting another member to such a base metal there are known such techniques as welding, bonding, and mechanical clamping.
The welding technique is advantageous in that the bonding strength is high, but is disadvantageous in that a large-scaled and expensive equipment is required and that a large space is needed for ensuring safety.
The bonding technique, in comparison with the welding technique, is advantageous in that the cost is low and that the bonding work can be done in a small space, but is disadvantageous in that it is necessary to keep the posture of base metals constant until an adhesive used solidifies, thus requiring a long time for bonding.
In the case of welding or bonding, when bonded base metals are not bonded to a satisfactory extent and are therefore to be re-bonded or when base metals are to be recycled, it is very difficult to disassemble the base metals from the bonded portion without any damage to the base metals.
On the other hand, as to mechanical clamping, various clamping techniques are known. Screw clamping, pin clamping and rivet clamping are mentioned as typical mechanical clamping techniques.
As to screw clamping there are known, for example, such a method as shown in FIG. 18(a) in which a bolt 3 as a clamping member inserted into clamping holes 1a and 2a formed in base metals 1 and 2 and a nut 4 as a clamping member engaged threadedly with the bolt 3 are tightened using a spanner to join the base metals 1 and 2 mechanically and such a method as shown in FIG. 18(b) in which, with use of a screw-driver, a tapping screw 5 as a clamping member is brought into threaded engagement with threads formed in clamping holes 1a and 2a of base metals 1 and 2, to clamp the base metals, thereby joining the base metals mechanically.
As to pin clamping there are known, for example, such a method as shown in FIG. 19(a) in which a pin 6 as a clamping member is inserted into clamping holes 1a and 2a and is then caulked at both ends thereof by means of a caulking machine or a caulking tool to join base metals 1 and 2 mechanically and such a method as shown in FIG. 19(b) in which a shaft 7 as a clamping member is inserted into a clamping hole of a base metal 1 and is then caulked at an end portion thereof by means of a caulking machine or a caulking tool to connect the shaft 7 to the base metal 1 mechanically.
As to rivet clamping there are known a method in which a solid rivet 8 as a clamping member shown in FIG. 20(a) and a tubular rivet 9 as a clamping member shown in FIG. 20(b) are each inserted into clamping holes 1a and 2a of base metals 1 and 2 and are then squeezed at respective end portions to connect the base metals with each other mechanically and a method in which a blind rivet 10 as a clamping member shown in FIG. 20(c) is inserted into clamping holes 1a and 2a of base metals 1 and 2 and is then squeezed at an end portion thereof using a mandrel which will be described later to connect the base metals 1 and 2 with each other mechanically, as shown in FIG. 20(f).
The blind rivet 10, as shown in FIG. 20(c), comprises a rivet body 11 and a mandrel 12 inserted into an axial hole 11a of the rivet body 11. For example, base metals 1 and 2 are clamped together mechanically in accordance with the following procedure.
According to this rivet clamping method, first a body portion 11b of the blind rivet 11 is inserted into clamping holes 1a and 2a of base metals 1 and 2, as shown in FIG. 21(a), and a blind rivet clamping device 13 is set at an end portion of the mandrel 12, as shown in FIG. 21(b).
Then, as shown in FIG. 21(c), a nose piece 13a of the blind rivet clamping device 13 is brought into close contact with a head portion 11c of the rivet body 11 and the blind rivet clamping device 13 is triggered while the head portion 11c is pushed against the base metal 1 by the nose piece 13a. 
As a result, the mandrel 12 is gripped by a jaw member 13b as a clamp shaft gripping member of the blind rivet clamping device 13 and is pulled in the direction opposite to the pushing direction, then the portion of the body portion 11b projecting from the back side of the base metal 2 is deformed plastically and squeezed and is caulked into pressure contact with the base metal 2.
In this state, if the jaw member 13b is further pulled in the direction opposite to the pushing direction, the mandrel 12 will be broken at a reduced-diameter portion 12b thereof, so that the base metals 1 and 2 are clamped together by the blind rivet 10, as shown in FIG. 21(d).
In this clamping work using the blind rivet 10, the mandrel is thus pulled in the direction opposite to the pushing direction and therefore, as shown in FIGS. 21(a) to 21(d), the clamping work for the base metals 1 and 2 can be carried out without supporting the back side of the base metals. Thus, this method is suitable for clamping the base metals 1 and 2 in such a place where the worker""s hand cannot reach the back side of the base metals.
There also is known a mechanical clamping technique called burring caulking in which, as shown in FIG. 22, a shaft 7 (body portion 11b) integral with one base metal 1 is caulked to a clamping hole 2a of the other base metal 2 to clamp both base metals together mechanically.
Such a mechanical clamping technique is advantageous in that, as compared with the welding technique, the clamping work can be done easily while ensuring safety and even in a narrow space without requiring a large-sized equipment. Further, it is advantageous in that the base metals 1 and 2 can be clamped together rapidly in comparison with the bonding technique.
However, the clamping member used in such mechanical clampings as pin clamping, rivet clamping and burring caulking is clamped to base metals by a plastic deformation of its body portion, so when the clamping member is not properly clamped to base metals and so must be removed from the base metals or when base metals are to be recycled and therefore must be removed from the clamping member, it is necessary to disassemble the clamping member. However, this disassembling work requires much time and labor and there is a fear that the base metals may be damaged in the disassembling work. More particularly, as a disassembling method for this type of a clamping member there is known such a method as shown in FIG. 23. An example thereof will be described below with respect to disassembly of the blind rivet 10 as a clamping member.
First, with a drill 14, the head portion 11c of the blind rivet 10 is cut and removed from the body portion 11b. Then, by tapping the cut portion in a direction in which the body portion 11b comes out of the clamping holes 1a and 2a, the blind rivet 10 is pulled out from the base metals 1 and 2.
Such a conventional blind rivet disassembling method requires much time and labor for preparatory works, including selection of the drill 14 and the cutting work. Moreover, in cutting the head portion 11c, if the tip of the drill 14 reaches the base metal 1 and cuts the clamping hole 1a of the base metal 1, with consequent increase in size of the clamping hole 1a, as shown in FIG. 24, it will be impossible to ensure a sufficient clamping force even if this base metal 1 is recycled and re-clamped using the blind rivet 10, Generally, once the base metals 1 and 2 are flawed in the blind rivet disassembling work, it becomes difficult to recycle such base metals.
Further, in the case of using this type of a drill in the clamp member disassembling work, the clamping member undergoes a follow-up rotation with rotation of the drill 14 at the time of cutting the head portion 11c of the clamping member, thus giving rise to the problem that the base metal 1 is scratched or it is impossible to cut the head portion 11c. Particularly, when the base metal 1 is used as an outer component of a product, a scratch, if any, on the surface of the base metal 1 will markedly deteriorate the commercial value of the product. Therefore, such a scratched base metal 1 cannot be recycled, and if it should be recycled, the percent defective of the base metal at the time of disassembly would become very high.
Therefore, to prevent the follow-up rotation of the clamping member with rotation of the drill 14, the head portion 11c is cut by the drill 14 while the head portion 11c or the body portion 11b is gripped by a gripping tool 15 such as pliers or pincers to prevent the follow-up rotation, as shown in FIG. 23, However, this work is performed by two or more workers because it is dangerous if this work is done by one worker, resulting in an increase of personnel expenses in the disassembling work.
Particularly, when the head portion 11c of the clamping member is in a flat shape and is difficult to be gripped by the gripping tool 15 and when the base metals 1 and 2 are clamped by the clamping member in such a place where the worker""s hand cannot reach the back side of the base metals, it is difficult to prevent the follow-up rotation because the body portion 11b cannot be gripped by the gripping tool 15.
In the case of such screw clamping as shown in FIGS. 18(a) and 18(b), bolt 3, nut 4 and tapping screw 5 as clamping members can in many cases be removed easily from the base metals 1 and 2, but even in the use of a screw, if the threaded portions of the bolt 3 and the nut 4 are fastened with rust or if the threaded portions of the tapping screw 5 and the clamping holes 1a, 2a are in a mutually adhered state, there occurs an inconvenience such that the screw threads are damaged and the clamping member comprising the bolt 3 and the nut 4 idles relative to the base metals 1 and 2. Moreover, if a polygonal head portion of the bolt 3, an angular portion of the nut 4, or the head portion of the tapping screw 5 is damaged, it becomes very difficult to remove such damaged component.
It is an object of the present invention to provide a clamping member disassembling device and method capable of removing a clamping member as clamped to base metals from the base metals easily and rapidly without damage to the base metals, as well as an attachment structure thereof and a production system using the disassembling method.
For achieving the above-mentioned object, in the first aspect of the present invention, there is provided a clamping member disassembling device for disassembling a clamping member from base metals, the clamping member comprising a head portion and a body portion and being clamped to the base metals, with the body portion being inserted into clamping holes formed in the base metals and the head portion being in contact with a peripheral edge portion of the clamping hole in one of the base metals, the clamping member disassembling device comprising a cutting means for cutting the body portion of the clamping member in a direction nearly perpendicular to an axial direction of the body portion, a moving means for advancing and retreating the cutting means in the axial direction of the body portion, and a motion changing means for actuating the cutting means in a direction nearly perpendicular to the axial direction of the body portion with an advancing or retreating motion of the cutting means.
According to this construction, the clamping member clamped to the base metals can be removed from the base metals easily and rapidly without damage to the base metals.
In the second aspect of the present invention there is provided, in combination with the first aspect, a clamping member disassembling device further including a keeping means for keeping the cutting means at a certain position in the axial direction of the body portion of the clamping member when the body portion is cut by the cutting means.
In the third aspect of the present invention there is provided, in combination with the first aspect, a clamping member disassembling device further including a pulling means which pulls the head portion of the clamping member through the cutting means away from the body portion in the axial direction of the body portion while the body portion is gripped by the cutting means in a cutting work.
According to this constructions, the head portion can be cut off while it is torn off.
In the fourth aspect of the present invention there is provided a clamping member disassembling device for disassembling a clamping member from base metals, the clamping member comprising a head portion and a body portion and being clamped to the base metals, with the body portion being inserted into clamping holes formed in the base metals and the head portion being in contact with a peripheral edge portion of the clamping hole in one of the base metals, the clamping member disassembling device comprising a cutting means for cutting the clamping member and an actuator for actuating the cutting means, the cutting means comprising blades for cutting a boundary region perpendicular to an axial direction of the body portion and positioned between the body portion and the head portion, in opposite directions with respect to the axis of the body portion, a grip portion substantially integral with the blades and adapted to cause the blades to substantially advance and retreat in interlock with advancing and retreating motions of the actuator while being gripped by the actuator, and a motion changing means for changing the motion of the blades into an opening or closing motion in directions nearly perpendicular to the axial direction of the body portion of the clamping member with an advancing or retreating motion of the blades, and the actuator causing the cutting means to advance and retreat while gripping the grip portion to separate the head portion and the body portion from the boundary region.
According to this construction, the head portion and the body portion can be cut from each other automatically with use of a drive source without using a manual cutting force.
In the fifth aspect of the present invention there is provided, in combination with the fourth aspect, a clamping member disassembling device further including a contact/holding means, the contact/holding means having a contact portion for contact with the head portion or the base metals and also having a fixed portion fixed substantially to a body of the disassembling device, the contact/holding means being adapted to hold the body of the disassembling device at a predetermined position relative to the base metals, thereby allowing the blades to cut the boundary region and allowing the head portion to be pulled in a direction where the disassembling device body is present.
In the sixth aspect of the present invention there is provided, in combination with the fourth aspect, a clamping member disassembling device wherein the motion changing means is substantially integral with the grip portion, and the cutting means possesses elasticity and has an outer peripheral surface formed as an inclined surface which is inclined outward in a direction in which the blades are present.
In the seventh aspect of the present invention there is provided, in combination with the fourth aspect, a clamping member disassembling device wherein the motion changing means is substantially integral with the grip portion.
In the eighth aspect of the present invention there is provided, in combination with the seventh aspect, a clamping member disassembling device wherein the cutting means possesses elasticity and has an outer peripheral surface formed as an inclined surface which is inclined outward in a direction in which the blades are present.
In the ninth aspect of the present invention there is provided an attachment structure having an attachment unit to be attached to a blind rivet clamping device to disassemble a blind rivet, in which clamping device a body portion of the blind rivet integral with a head portion of the blind rivet is inserted into clamping holes formed in base metals and a mandrel of the blind rivet is gripped and pulled to clamp the blind rivet, the attachment unit comprising a cutting means for cutting a boundary region between the body portion and the head portion of the blind rivet from both sides toward an axial direction of the body portion, the boundary region being substantially perpendicular to the axial direction of the body portion, a grip means to be gripped by an actuator of the blind rivet disassembling device so as to cause the cutting means to advance and retreat in the axial direction of the body portion, and a motion changing means which actuates the cutting means in a direction nearly perpendicular to the axial direction of the body portion with an advancing or retreating motion of the grip means.
In the tenth aspect of the present invention there is provided, in combination with the ninth aspect, an attachment structure further including a keeping means for keeping the cutting means at a certain position in the axial direction of the body portion when the body portion is cut by the cutting means.
In the eleventh aspect of the present invention there is provided, in combination with the ninth aspect, an attachment structure further including a pulling means which pulls the head portion through the cutting means away from the body portion in the axial direction of the body portion while the body portion is gripped by the cutting means in a cutting work.
In the twelfth aspect of the present invention there is provided an attachment structure having an attachment unit to be attached to a blind rivet clamping device to disassemble a blind rivet, in which clamping device a body portion of the blind rivet integral with a head portion of the blind rivet is inserted into clamping holes formed in base metals and a mandrel of the blind rivet is gripped and pulled to clamp the blind rivet, the blind rivet clamping device having an actuator for actuating the attachment unit, the attachment unit having a cutting means for cutting the blind rivet, the cutting means comprising blades for cutting a boundary region perpendicular to an axial direction of the body portion and positioned between the body portion and the head portion, in opposite directions with respect to the axis of the body portion, a grip portion substantially integral with the blades and adapted to cause the blades to substantially advance and retreat in interlock with advancing and retreating motions of the actuator while being gripped by the actuator, and a motion changing means for changing the motion of the blades into an opening or closing motion in a direction nearly perpendicular to the axial direction of the body portion of the clamping member with an advancing or retreating motion of the blades, and the actuator causing the cutting means to advance and retreat while gripping the grip portion to separate the head portion and the body portion from the boundary region.
According to the constructions in the above ninth to twelfth aspects, the boundary region between the head portion and the body portion can be cut by utilizing an existing blind clamping device.
In the thirteenth aspect of the present invention there is provided, in combination with the twelfth aspect, an attachment structure wherein the attachment unit is further provided with a contact/holding means having a first contact portion and a second contact portion, the first contact portion being adapted to contact one of the base metals to fix the cutting means, the second contact portion being brought into engagement with a front end of the blind rivet clamping device, allowing the cutting means to be substantially fixed to the blind rivet clamping device, and the cutting means pulls the head portion of the blind rivet toward the blind rivet clamping device while cutting the boundary region.
In the fourteenth aspect of the present invention there is provided, in combination with the twelfth aspect, an attachment structure wherein the motion changing means is substantially integral with the grip portion, and the cutting means possesses elasticity and has an outer peripheral surface formed as an inclined surface which is inclined outward in a direction in which the blades are present.
In the fifteenth aspect of the present invention there is provided, in combination with the twelfth aspect, an attachment structure wherein the motion changing means is substantially integral with the grip portion.
In the sixteenth aspect of the present invention there is provided, in combination with the fifteenth aspect, an attachment structure wherein the cutting means possesses elasticity and has an outer peripheral surface formed as an inclined surface which is inclined outward in a direction in which the blades are present.
According to the constructions in the above thirteenth to sixteenth aspects, the head portion can be torn off from the body portion by utilizing an existing blind rivet clamping device.
In the seventeenth aspect of the present invention there is provided a clamping member disassembling method for disassembling a clamping member from base metals, the clamping member comprising a head portion and a body portion and being clamped to the base metals, with the body portion being inserted into clamping holes formed in the base metals and the head portion being in contact with a peripheral edge portion of the clamping hole in one of the base metals, which method comprises causing at least a pair of edges of blades to face between the head portion of the clamping member and the base metals, the blades capable of being opened and closed with respect to each other and the edges thereof being adapted to engage each other, causing in this state an actuator of a cutting force output unit to advance or retreat, the cutting force output unit outputting a cutting force for cutting off the head portion and the body portion from each other, changing the advancing or retreating motion of the actuator into an opening or closing motion for opening or closing the blades along a boundary between the head portion of the clamping member and the base metals, through a motion direction changing means, and allowing the edges of the blades to be engaged with each other by the closing motion of the blades to cut off the body portion.
According to this construction there is obtained the same effect as in the fourth aspect.
In the eighteenth aspect of the present invention there is provided a clamping member disassembling method wherein a clamping member which clamps at least two base metals is removed to unclamp the base metals, the clamping member comprising at least a body portion to be inserted into clamping holes of the base metals and a head portion having an outside diameter larger than an inside diameter of each of the clamping holes, the head portion being brought into pressure contact with a peripheral edge portion of the clamping hole in one of the base metals, the method comprising causing a breaking member to get into a boundary region as a contact portion between the base metals and the head portion, and causing the breaking member to move away from the head portion in a state in which the breaking member has entered the boundary region, thereby breaking the head portion from the body portion.
According to this construction it is possible to tear off the head portion from the body portion.
In the nineteenth aspect of the present invention there is provided a production system wherein a clamping member comprising a head portion and a body portion and clamped to base metals, with the body portion being inserted into clamping holes formed in the base metals and the head portion being in contact with a peripheral edge portion of the clamping hole in one of the base metals, is removed and the base metals are recovered, the production system including a clamping member disassembling device, the clamping member disassembling device comprising a cutting means for cutting off the body portion in a direction nearly perpendicular to an axial direction of the body portion, a moving means for advancing and retreating the cutting means in the axial direction of the body portion, and a motion changing means which actuates the cutting means in a direction nearly perpendicular to the axial direction of the body portion with an advancing or retreating motion of the cutting means, and in which production system the clamped condition of the clamping member to the base metals is checked and if it is found to be defective, the clamping member is removed from the base metals and the base metals are recovered.
In the twentieth aspect of the present invention there is provided a production system wherein a clamping member comprising a head portion and a body portion and clamped to base metals, with the body portion being inserted into clamping holes formed in the base metals and the head portion being in contact with a peripheral edge portion of the clamping hole in one of the base metals, is removed and the base metals are recovered, the production system including a clamping member disassembling device, the clamping member disassembling device comprising a cutting means for cutting off the body portion in a direction nearly perpendicular to an axial direction of the body portion, a moving means for advancing and retreating the cutting means in the axial direction of the body portion, and a motion changing means which actuates the cutting means in a direction nearly perpendicular to the axial direction of the body portion with an advancing or retreating motion of the cutting means, wherein the clamping member is removed from the base metals and the base metals are recovered.
According to the constructions in the above nineteenth and twentieth aspects it is easy to recover the base metals from which the clamping member has been disassembled and removed.